From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Page 2 of a memo outlining design considerations for engine valve, carburetter, and exhaust systems.
| Identifier | ExFiles\Box 65a\3\ scan0280 | |
| Date | 7th April 1931 | |
| Hs{Lord Ernest Hives - Chair}/Lov{Mr Lovesey}2/ADL 7.4.31 contd. -2- (2) We wish to control the valves up to 3500 R.P.M. Several designs for multiple valve springs exist and we should look these out and see what is the maximum valve lift these will allow. Also determine what is the highest lift cam we could employ from the point of view of - (a) Bottom tappet travel. (b) Push rod movement in the tubes in cylinder. Will high lift cause these to foul the tubes? It may be necessary to use steel rods of smaller diameter. (c) Rocker angular movement. Does interference take place at push rod end and does valve end travel off ground pad? (d) What valve springs did we employ on previous high speed experiments? We think the inner springs were from 'Eagles'. What was the bouncing speed of these valves and what pressure did they exert on the valve closed and open. From the above we should know what is the limit of valve lift we can employ. (3) Carburetters and Induction system. We want to keep the capacity of the induction system as small as possible to allow maximum ramming for low speed performance as found on 25 HP. and Phantom I and Phantom II. at the same time we want large and free induction passages for high speed. This demands two separate carburetters - look out two Eagle or Falcon carburetters of the appropriate size. Look up our distribution tests and confirm if the simple inverted L shaped pipes gave the best results. We should then scheme a pipe keeping the distances as short as possible. (4) Exhaust system. Previous experiments have shewn loss in power with single exhaust down pipe. First we want :- | ||